1) Shaytan refused to prostrate in front of Adam (as), he always believed and worshipped Allah. He not only disobeyed Allah but He refused to repent and still considered himself better than Adam. Thus, he never sought forgiveness, and was defiant
2) Allah does not create evil or the potential to be evil, it is the power of choice and temptation that causes creation to err. God is all-Forgiving, but Shaytan was arrogant and didn’t want forgiveness, instead he defiantly dared Allah that he will cause His creation to go astray